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Sum of 1 to 100 Worksheet

Maths tricks trick 8: Add 1 to 100 in seconds · Set 292 · 40 questions
TalentJR

The trick (Pairs): Pair the first and last numbers: each pair adds to n + 1. Count the pairs — or multiply n × (n + 1) and halve it. Odd numbers 1 + 3 + 5 + …: count them and multiply that count by itself.

NameDateTime takenScore ___ / 40
  1. 1.1 + 2 + 3 + … + 60 =
  2. 2.1 + 2 + 3 + … + 51 =
  3. 3.1 + 2 + 3 + … + 39 =
  4. 4.1 + 2 + 3 + … + 92 =
  5. 5.1 + 2 + 3 + … + 80 =
  6. 6.1 + 3 + 5 + … + 15 =
  7. 7.1 + 2 + 3 + … + 9 =
  8. 8.1 + 3 + 5 + … + 11 =
  9. 9.1 + 3 + 5 + … + 27 =
  10. 10.1 + 2 + 3 + … + 52 =
  11. 11.1 + 2 + 3 + … + 7 =
  12. 12.1 + 3 + 5 + … + 43 =
  13. 13.1 + 2 + 3 + … + 86 =
  14. 14.1 + 2 + 3 + … + 76 =
  15. 15.1 + 2 + 3 + … + 30 =
  16. 16.1 + 2 + 3 + … + 32 =
  17. 17.1 + 3 + 5 + … + 45 =
  18. 18.1 + 2 + 3 + … + 63 =
  19. 19.1 + 3 + 5 + … + 41 =
  20. 20.1 + 3 + 5 + … + 25 =
  21. 21.1 + 3 + 5 + … + 17 =
  22. 22.1 + 2 + 3 + … + 37 =
  23. 23.1 + 2 + 3 + … + 8 =
  24. 24.1 + 2 + 3 + … + 67 =
  25. 25.1 + 2 + 3 + … + 6 =
  26. 26.1 + 3 + 5 + … + 13 =
  27. 27.1 + 2 + 3 + … + 79 =
  28. 28.1 + 2 + 3 + … + 33 =
  29. 29.1 + 2 + 3 + … + 40 =
  30. 30.1 + 2 + 3 + … + 66 =
  31. 31.1 + 2 + 3 + … + 90 =
  32. 32.1 + 3 + 5 + … + 47 =
  33. 33.1 + 3 + 5 + … + 23 =
  34. 34.1 + 2 + 3 + … + 23 =
  35. 35.1 + 2 + 3 + … + 26 =
  36. 36.1 + 3 + 5 + … + 39 =
  37. 37.1 + 2 + 3 + … + 89 =
  38. 38.1 + 2 + 3 + … + 12 =
  39. 39.1 + 2 + 3 + … + 55 =
  40. 40.1 + 2 + 3 + … + 73 =

Answer key

  1. 1830
  2. 1326
  3. 780
  4. 4278
  5. 3240
  6. 64
  7. 45
  8. 36
  9. 196
  10. 1378
  11. 28
  12. 484
  13. 3741
  14. 2926
  15. 465
  16. 528
  17. 529
  18. 2016
  19. 441
  20. 169
  21. 81
  22. 703
  23. 36
  24. 2278
  25. 21
  26. 49
  27. 3160
  28. 561
  29. 820
  30. 2211
  31. 4095
  32. 576
  33. 144
  34. 276
  35. 351
  36. 400
  37. 4005
  38. 78
  39. 1540
  40. 2701

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